In the transfer of petroleum materials, such as in marine transfer operations between ships and barges and onshore facilities, there are often discharged off-gases which contain environmentally unacceptable amounts of a light hydrocarbon fraction. It is desirable to reduce the amount of light hydrocarbon fractions in discharge off-gasses, both for environmental concerns and for the economic value of the recovery of the light hydrocarbon fractions.
Generally, a particulate-containing adsorbent type column, such as activated carbon columns, are employed in marine transfer operations to adsorb the light hydrocarbon fraction vapors. However, difficulties do occur when large off-gas and light hydrocarbon vapor amounts are present, such as in marine loading and unloading operations, due to the volume of the light hydrocarbon fraction discharge and the rapid adsorption of the light hydrocarbon and the need to regenerate such columns frequently. Thus in marine petroleum transfer operations, the employment of activated carbon or other particulate-type adsorbent columns to recover a light hydrocarbon fraction from the off-gases, is often a complex, cumbersome and expensive recovery operation, which involves the frequent desorption of the activated carbon by heating or by the employment of large vacuum pumps.
It is therefore desirable to provide a new, improved, efficient integrated process for the recovery of a light hydrocarbon fraction, particularly from marine loading operations and to provide for the discharge of gases having an environmentally acceptable amount of the light hydrocarbon fraction.